US11051864B2 - Intramedullary fixation assembly - Google Patents

Abstract

Intramedullary fixation assemblies (4, 8) and intramedullary fixation devices (1, 24) can be used in orthopaedic surgery for the fixation of bone fractures. Also disclosed is an insertion device (30) for inserting an intramedullary fixation device, and a method of fixing a bone fracture. The fixation devices are preferably for addressing fractures of the distal radius, and are preferably styloid nails. The styloid nails preferably have a head portion that can accept up to three bone screws; one of the bone screws is designed to extend across a fracture line between a proximal and a distal bone fragment while the other bone screws are designed to be retained in the distal bone fragment.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/695,254 filed Aug. 30, 2012 and Application Ser. No. 61/723,016 filed Nov. 6, 2012, the contents of which are hereby incorporated by reference herein in their entirety.

TECHNICAL FIELD

The present disclosure relates to intramedullary fixation devices, methods for fixing bone fractures and devices for inserting intramedullary fixation devices.

BACKGROUND

The use of intramedullary fixation devices to fix bone fractures is well known in the orthopaedic field. With those nails known in the art, a surgeon will have to make multiple skin incisions, and drill multiple bone holes in order to implant the nails. This results in a long, complicated procedure requiring multiple instruments and resulting in multiple traumas to the patient.

Also, WO 02/024088 discloses an intramedullary interlocking fixation rod to fix a bone fracture comprising an intramedullary nail which requires anchoring of its head by a screw in the articular fragment of the bone and anchoring of its tail in the medullary canal of the second fragment of the bone with two further screws. Due to the requirement of screws at multiple positions on the fixation rod, multiple skin incisions and bone holes are required for insertion of the nail.

There is therefore a need in the art for nail devices for fixing bone fractures that require fewer skin incisions, fewer bone holes and that do not require a multitude of instruments for implantation.

SUMMARY

In a first aspect, an intramedullary fixation assembly can include an intramedullary fixation device, such as an intramedullary nail, and at least one fixation element, such as a plurality of fixation elements. The intramedullary fixation device can be dimensioned to lie in a medullary canal of a bone when implanted, the intramedullary nail including:

• • a head from which a shaft extends defining an insertion axis, and
  • a body, and plurality of insertion channels arranged through the body, the insertion channels configured to receive the fixation elements, respectively, therethrough, each insertion channel defining an insertion point, an exit point and a channel axis passing through the insertion point and the exit point;

The head may comprise an insertion area in which each insertion point of the plurality of insertions channels is located. The insertion area may be dimensioned and positioned to remain accessible through a hole in a bone through which the intramedullary nail has been inserted.

The intramedullary fixation device may be completely inserted and fixed in position through a single hole in a bone. Fixation of the intramedullary fixation device is possible with only a single skin incision and through the making of a single bone hole. Additional locking of the end of the intramedullary fixation device opposed to the insertion area is unnecessary.

All insertion channels of the intramedullary fixation device may have their insertion points located in the insertion area.

The insertion area may be the only area in the nail having insertion points through which fixation elements can be inserted.

The insertion axis and each of the plurality of channel axes may diverge with respect to each other away from the insertion area. The insertion axis and plurality of channel axes pyramidally may diverge with respect to each from the insertion area.

The plurality of insertion channels may include, and can be limited to, two insertion channels. When implanted, one of the insertion axis or one of the channel axes of the two insertion channels may extend in a direction from a first bone fragment to a second bone fragment, the bone fragments separated by a fracture, and the other two of the insertion axis and the channel axes of the two insertion channels may extend within the first bone fragment.

Alternatively, the plurality of insertion channels may include, and can be limited to, three insertion channels. When implanted, two of the insertion axis or the channel axes of the three insertion channels may extend in a direction from a first bone fragment to a second bone fragment, the bone fragments separated by a fracture, and the other two of the insertion axis and the channel axes of the three insertion channels may extend within the first bone fragment.

The intramedullary fixation assembly, including the intramedullary fixation device and the fixation elements, may restrict motion in up to six dimensions and have the effect of ensuring that the bone fracture is stably reduced and thereby supporting bone healing. In particular, the combination of the intramedullary nail and the three insertion channels has the effect of restricting motion in six dimensions.

One of the channel axes may be a coaxial channel axis. A portion of the coaxial channel axis may be substantially coaxial with the insertion axis. The intramedullary fixation device can include a body, and the insertion channel having the coaxial channel axis may run through the body of the intramedullary fixation device from its insertion point to its exit point, the exit point being located in the shaft. The insertion axis may curve away from the coaxial channel axis in the vicinity of the exit point in a direction from the exit point to the end of the shaft.

At least one of the plurality of insertion channels may have a seating area configured to locking hold a portion of a fixation element therein. The seating area may be located adjacent an insertion point of one of the plurality of insertion channels, said one of the plurality of insertion channels has its exit point located in the shaft. Each one of the plurality of insertion channels may have a seating area configured to locking hold a portion of a fixation element therein, each seating area located adjacent respective insertion points.

The intramedullary fixation device can include a body, which can be a nail body (for instance, when the intramedullary fixation device is an intramedullary nail such as a styloid nail) that can have a curvilinear shape and the shaft may be configured to be elastically deformable to conform to the shape of the medullary canal during implantation. The shaft of the nail body can be substantially smooth and devoid of threads.

The shaft of the body of the intramedullary fixation device may body be threaded.

The head may be shaped to reside within a head of a long bone, such as the styloid region of a long bone.

The head may be dimensioned to reside within a head of a long bone, such as the styloid region of a long bone.

The intramedullary fixation assembly can include the intramedullary fixation device, which can be a styloid nail device, for fixing a bone fracture. The styloid nail device may comprise a first longitudinal fixation element configured to pass across the fracture line between a first bone fragment and a second bone fragment. The intramedullary fixation assembly can further include a plurality of second fixation elements configured to anchor the styloid nail device in the first bone fragment.

The head of the first longitudinal fixation element may be configured to accommodate the plurality of second fixation elements further, and one of the second fixation elements may be configured to pass from a distal bone fragment to a proximal bone fragment.

The first longitudinal fixation element may be flexible and bowed. This may improve the anchoring of the styloid nail device in the medullary canal of the bone.

As used herein, a distal bone fragment is the fragment of a fractured bone in which the fracture line is closest to a joint. For example, the distal fragment is an articular bone fragment, and the fracture may be an extra articular fracture. An extra articular fracture is a fracture where the bone has not penetrated the skin, contains only one complete fracture line, and the fracture line does not intersect with part of the joint.

The second fixation elements may be screws or staples which have a longitudinal core. The longitudinal cores of the second fixation elements, and also the first fixation element, may be identical. Having fixation elements with the same core diameter provides the advantage that a reduced number of instruments are needed for implantation of the intramedullary fixation assembly (as compared to an assembly comprising elements with differing diameters), thereby reducing the complexity and costs of the implantation procedure.

As used herein, the “core” of a screw refers to the longitudinal shaft of the screw upon which the thread resides.

The intramedullary fixation assembly may have at least three second fixation elements, which may be screws, wherein the second fixation elements are mounted in the head of the first longitudinal fixation element so as to form a pyramidal engagement with a bone fragment. The pyramidal engagement prevents all rotation and separation of the bone fragments, with the exception of micromovements. Therefore, a stable fixation of the bone can be achieved, whilst minimal instrumentation is needed to insert the styloid nail device and minimal trauma is caused to the patient as few incisions in the skin and bone holes are required.

The head of the longitudinal first fixation element may have holes that are threaded to receive the second fixation elements. Advantageously, this increases the stability of the intramedullary fixation device.

The intramedullary fixation device may be an intramedullary nail or screw. The term “intramedullary” is known in the art and denotes that the nail resides at least partly in the medullary canal of the bone.

Two of the second fixation elements may be screws configured to be located in a distal bone fragment, and a tail of a third second fixation element is configured to pass from the distal bone fragment to a proximal bone fragment across a fracture line, and wherein at least a portion of the second fixation element that crosses the fracture line is configured to extend longitudinally through the first fixation element. The advantage associated with this particular configuration, especially where the second fixation elements form a pyramidal engagement with the bone fragment, is that a stable fixation of the bone is achieved with the requirement of only one skin incision and one bone hole to implant the styloid nail device.

In a second aspect, an intramedullary fixation device can be pass from a first bone fragment to a second bone fragment across a fracture line, wherein the intramedullary fixation device is threaded. Further, the second aspect also provides an intramedullary fixation assembly that includes the intramedullary fixation device and a first fixation element, wherein the intramedullary fixation device is adapted to be received in a head of the first fixation element, such that the intramedullary fixation device can be anchored in a distal bone fragment, wherein the head of the first fixation element is adapted to further accommodate a plurality of second fixation elements.

At least one of the second fixation elements of the second aspect may be configured to pass between a first bone fragment and a second bone fragment across a fracture line, in use.

The first and second fixation elements of the second aspect may be screws which may have longitudinal cores, which may have the same core diameter. As with the first aspect, this has the advantage that less instrumentation is required for implantation.

In a third aspect, an intramedullary fixation assembly may have an intramedullary fixation device having a body dimensioned to lie in a medullary canal of a bone when implanted, the body having:

• • a head from which a shaft extends;
  • a first insertion channel for receiving a fixation element therethrough, the first insertion channel defining an insertion point and an exit point, and
  • a second insertion channel for receiving a fixation element therethrough, the second insertion channel defining an insertion point and an exit point.

The head may comprise an insertion area in which the insertion points of the first and second insertions channels are located. The insertion area may be dimensioned and positioned to remain accessible through a hole in a bone through which the nail body has been inserted.

The intramedullary fixation assembly also has a first fixation element for insertion in the insertion point of the first insertion channel and a second fixation element for insertion in the insertion point of the second insertion channel.

When implanted at least one of the shaft, the first fixation element and the second fixation element is a bridging element arranged to span across a bone fracture from a first bone fragment to a second bone fragment, and thus is an intramedullary fixation device, and at least one of the shaft, the first fixation element and the second fixation element is arranged to lie within the first bone fragment.

The intramedullary fixation assembly of the third aspect has a bridging element for allowing a second bone fragment to be fixed to a first bone fragment through insertion of the bridging element in the vicinity of a single bone hole.

A fixation element separate from the intramedullary fixation assembly may be additionally inserted from the first to the second bone fragment to lock the bone fragments together and restrict motion in six dimensions.

The bridging element may have a multi-faceted outer surface for engaging with a medullary canal of the first and second bone fragments.

The body of the intramedullary fixation device, which can be a nail, may have a third insertion channel for receiving a fixation element therethrough. The third insertion channel may define an insertion point and an exit point. The head may have an insertion area in which the insertion points of the first, second and third insertions channels are located. The insertion area may be dimensioned and positioned to remain accessible through a hole in a bone through which the nail body has been inserted. The intramedullary fixation assembly may have a third fixation element. When implanted two of the shaft and the first, second and third fixation elements may be bridging elements and the other two of the shaft and the first, second and third fixation elements may lie within the first bone fragment.

The intramedullary nail may be inserted in a minimally invasive manner through a single incision in skin, and other soft tissue, and through making a single hole in a bone to be fixated. The combination of the intramedullary nail and first through third fixation elements lock the second bone fragment to the first bone fragment and restrict motion in six dimensions to support bone healing using minimally invasive techniques.

The insertion paths may be defined by the shaft and the plurality of insertion channels pyramidally diverging with respect to each other from the insertion area.

The fixation elements may form a pyramidal engagement with the bone, the angle between the elements at the vertex of the pyramid at the insertion area on the head of the intramedullary nail may all be different or equal and may be 109.5°, or 100°, or 90°, or 80°, or 70°, or 60°. There may be a pair of fixation elements in which the angle between them at the vertex of the pyramid is, for example 60° and the third fixation element is at an angle of 100° from each of the pair of fixation elements. For example, in aspect one, the third second fixation element (that may cross the bone fracture), is at an angle of about 100° from the second fixation elements that remain in the distal fragment of the bone, and the second fixation elements that remain in the distal fragment of the bone are at an angle of about 60°.

The insertion channels may be configured according to the type of fixation element they are to receive. The fixation elements may be, but are not limited to, being one of a locking screw, a variable angle locking screw or a staple.

The intramedullary nail of the third aspect may have any of the features of the intramedullary nail of the first aspect.

In a fourth aspect, an intramedullary fixation system may include an intramedullary fixation device according to the first aspect or the second aspect. The intramedullary fixation system also has an aiming arm. The aiming arm may be connectable to the intramedullary nail and may define a plurality of guide channels therein. Each guide channel may have a guide axis aligned with a respective channel axis of an insertion channel, the channel axes diverging from an insertion area defined in a head of the intramedullary nail.

The intramedullary fixation system may further include a measuring device for measuring the depth of insertion of a fixation element.

The aiming arm may include, consist of or consist essentially of a radiolucent material. The radiolucent material is polyether ether ketone (PEEK). The aiming arm may have an x-ray visible mark.

In a fifth aspect, a first fixation element can be adapted to receive an intramedullary fixation device, such that the intramedullary fixation device can pass across a bone fracture between a first bone fragment and a second bone fragment in use, the first fixation element being threaded to anchor the first fixation element in a first bone fragment, a head of the first fixation element being further shaped to receive at least one second fixation element. The head of the first fixation element may be threaded to receive the second fixation element.

The head of the fixation element of the fifth aspect may be shaped to accommodate second fixation elements such that they define a pyramidal anchor. The advantage associated with this particular configuration, especially where the second fixation elements form a pyramidal engagement with the bone fragment, is that a stable fixation of the bone is achieved with the requirement of only one skin incision and one bone hole to implant the styloid nail device.

The intramedullary fixation devices, including styloid nail devices, styloid nails, and fixation elements described herein may be used in the temporal bone of the skull, and the ulna, tibia and fibula styloid processes, or any suitable alternative long bone as desired. In particular, intramedullary fixation devices, including styloid nail devices, styloid nails, and fixation elements described herein are used to fix an extraarticular fracture of the distal radius, and are inserted through the styloid process of the distal radius.

The term “styloid process” is a term known in the art and refers to a projection of bone on the surface of a bone, that serves as a small attachment point for muscles.

The head of the first fixation element may have holes that are threaded to receive the intramedullary fixation device and second fixation elements. Advantageously, this increases the stability of the combination.

In a sixth aspect, a method of implanting an intramedullary fixation device in a medullary canal of a bone cam support bone healing of a bone fracture between a first bone fragment and a second bone fragment. The method may have the steps of:

• • aligning the first and second bone fragments;
  • making a hole in the cortical bone of the first bone fragment;
  • passing an intramedullary fixation device through the hole, the intramedullary fixation device having a head from which a shaft extends and a plurality of fixation element receiving channels, each one of the plurality of fixation element receiving channels having an insertion point located in an insertion area defined in the head;
  • inserting a first fixation element through an insertion point in the insertion area; and
  • inserting a second fixation element through a different insertion point in the insertion area.

At least one of the shaft, the first fixation element and the second fixation element so inserted may be a bridging element arranged to span from the first bone fragment to the second bone fragment across the bone fracture and at least one of the shaft, the first fixation element and the second fixation element is arranged to lie within the first bone fragment.

A measurement may be taken before insertion of each of the first and the second fixation elements for determining the length of the fixation element to be inserted.

The first and second fixation elements may have the same core diameter.

The shaft may be threaded.

The fixation elements may be inserted in a manner so as to form a stable pyramidal construct with the bone.

The first bone fragment may be an articular fragment.

The fracture may be an extraarticular fracture.

In a seventh aspect, a method of fixing a bone fracture comprises making a single skin incision. The advantages associated with an implantation that only requires a single skin incision will be recognised by those skilled in the art. For example, minimal trauma is caused to the patient therefore minimising healing time and minimising the possibility of complications resulting from the procedure. The method may further comprise making only a single bone hole, with the same advantages associated with a single skin incision.

The method of fixing a bone fracture may comprise i) making one skin incision, ii) drilling a hole in a distal fragment of the bone; iii) inserting a first fixation element into the distal bone fragment; iv) inserting at least one second fixation element into the distal bone fragment.

The first fixation element of the method may be inserted so as to pass from the distal bone fragment to the proximal bone fragment across a fracture line, and the second fixation element may be inserted through the first fixation element. This insertion may be through the head of the first fixation element and the second fixation element may be inserted so as to remain entirely in the distal bone fragment.

A measurement may be taken before the second fixation element is inserted. This measurement is used to determine the length required of the at least one second fixation element.

A further second fixation element may be inserted through the head of the first fixation element in a manner so as to pass from a distal bone fragment across a fracture line to a proximal bone fragment.

The advantage associated with this method is that a stable fixation can be achieved with only a single skin incision and single bone hole. Advantageously, this method may be carried out using the device for inserting an intramedullary fixation device of the type described herein. Therefore, a stable fixation of the bone is achieved using minimal instrumentation.

The method of fixing a bone fracture may comprise, i) making an incision in the skin; ii) inserting a wire in a distal bone fragment, substantially parallel to a joint in the distal fragment; iii) measuring a depth of the distal bone fragment; iv) drilling a hole in a distal bone fragment substantially parallel to a joint in the distal fragment; v) placing a screw in the hole drilled in the bone fragment; vi) drilling one or more further holes in the distal fragment; viii) inserting one or more screws in the distal fragment, at least one of which passes from the distal bone fragment to a proximal bone fragment across a fracture line.

The fixation elements may be inserted so as to form a stable pyramidal construct with the bone, with the advantages previously discussed for this type of construct.

The depth of the distal bone fragment may be measured by applying a measuring device to the wire inserted in the distal bone fragment, which is calibrated with the length of wire employed. The wire may have a diameter of 1.1 mm, and may be a K-wire, and where the bone is the radius, the wire may be inserted into the volar-ulnar canal.

As used herein, K-wire is a shortened form of Kirschner wire, a sterilised, sharpened, smooth stainless steel pin used widely in the orthopaedic art.

The hole in the distal bone fragment may be drilled by applying a drill over the inserted wire, the drill may have a diameter of 2.0 mm.

The screw may be inserted over the guide wire, after which point the guide wire is removed.

Before drilling one or more further holes in the distal fragment, a second guide wire, which may be a 1.1 mm K-wire, may be inserted. The drilling of the one or more further holes may then be performed over the second guide wire. A measurement may then be taken to measure the length required for the one or more screws in the distal fragment, by applying a measuring device to the second guide wire. The one or more screws may then be inserted over the guide wire, before removal of the guide wire.

The one or more further screws that pass from the distal bone fragment to a proximal bone fragment across a fracture line may be inserted over a guide wire, which may be a 1.1 mm K-wire, after a hole has been drilled from the distal bone fragment to the proximal bone fragment across the fracture line, wherein the hole was drilled over the guide wire.

The advantage of this method is that a stable fixation can be achieved with the use of minimal instrumentation.

In an eighth aspect, an insertion device is provided and is configured to insert an intramedullary fixation device in a bone having a fracture, the device comprising; i) a first part configured to insert a first fixation element longitudinally through a distal fragment of the bone and across a fracture line; ii) an aiming arm configured to insert a guide wire; and iii) a measuring device for measuring the depth of insertion of the guide wire.

Advantageously, the device for inserting an intramedullary fixation assembly can be used with certain aspects of the method of fixing a bone fracture.

The device of the eighth aspect may be configured to insert one or more second fixation elements into the distal fragment of the bone, through a head of the first fixation element. The device may be configured to insert the one or more second fixation elements via the aiming arm.

The device of the eighth aspect includes, consists of or consists essentially of a radiolucent material which may be polyether ether ketone. Advantageously, this allows the surgeon using the device to have a clear view of the wires, screws and nails being used in the device via x-ray imaging. The device may have an x-ray visible mark on the aiming arm, to help the surgeon aim the guide wire.

As used herein, radiolucent refers to a material that allows the passage of x-rays with little attenuation, thereby rendering the material not visible by x-ray imaging.

Advantageously, the device of the eighth aspect can be used to insert a styloid nail device which provides a stable construct in the bone, preventing all rotation and separation of the bone fragments (except micromovements), with only one skin incision and one bone hole. Minimal instrumentation is also required.

The intramedullary fixation assemblies, including the intramedullary fixation devices, may be used in the temporal bone of the skull, and the ulna, tibia and fibula styloid processes, or in any suitable alternative long bone.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described in detail with reference to the accompanying drawings, in which:

FIG. 1A is a perspective view of an intramedullary fixation assembly in accordance with one embodiment, shown implanted into a bone;

FIG. 1B is a top plan view of an intramedullary fixation assembly similar toFIG. 1A, but constructed in accordance with an alternative embodiment;

FIG. 1C is a side elevation view of an intramedullary fixation assembly similar toFIGS. 1A-B, but constructed in accordance with an alternative embodiment;

FIG. 2 is a top plan view of an intramedullary fixation assembly in accordance with another embodiment;

FIG. 3A is a perspective view of an intramedullary fixation assembly in accordance with another embodiment;

FIG. 3B is a top plan view of an intramedullary fixation assembly similar to the intramedullary fixation assembly illustrated inFIG. 3A, but constructed in accordance with an alternative embodiment;

FIG. 4A is a perspective view of an intramedullary fixation assembly in accordance with one embodiment;

FIG. 4B is a side elevation view of an intramedullary fixation assembly similar toFIG. 4A, but constructed in accordance with another embodiment;

FIGS. 5A-J show an insertion assembly and associated steps inserting and fixing an intramedullary fixation assembly in accordance with one embodiment;

FIG. 6A shows a first step of a method of fixing a bone fracture in accordance with one embodiment; and

FIG. 6B shows a second step of the method of fixing a bone fracture illustrated inFIG. 6A.

DETAILED DESCRIPTION

Referring toFIGS. 1A-1C generally, anintramedullary fixation assembly4, can include a bone fixation device, which can be configured as anintramedullary fixation device1. The term “intramedullary” is known in the art and denotes that the nail resides at least partly in the medullary canal of a bone. Theintramedullary fixation device1 can be elongate generally along acentral axis14. For instance, thecentral axis14, and thus theintramedullary fixation device1, can be bowed or generally curvilinear in shape along its direction of elongation. Theintramedullary fixation device1 is configured to reside in amedullary canal3 of a long bone, such as aradius5 that includes ashaft25, and a head orarticular fragment15 that extends distally from theshaft25.

In accordance with the illustrated embodiment, theintramedullary fixation device1 is sized and configured to extend across afracture location7 disposed between theshaft25 and thearticular fragment15. As used herein, a distal bone fragment can refer to the fragment of a fractured bone in which thefracture line7 is closest to a joint. For example, the distal fragment is thearticular bone fragment15, and the fracture may be an extra articular fracture. An extra articular fracture is a fracture where the bone has not penetrated the skin, contains only one complete fracture line, and the fracture line does not intersect with part of the joint. Thus, thearticular fragment15 can define a first or distal bone fragment, theshaft25 can define a second or proximal bone fragment, and thefracture location7 can separate the first bone fragment from the second bone fragment. As will be appreciated from the description below, theintramedullary fixation device1 is configured to be inserted through astyloid process19 of thearticular fragment15 and into themedullary canal3 so as to extend across thefracture7, and is further configured to be fixed to both thearticular fragment15 and theshaft25, thereby stabilizing the articular fragment and theshaft25 with respect to each other so as to promote bone fixation across thefracture7. Thus, theintramedullary fixation device1 can be referred to as a styloid fixation device. It should, of course, be appreciated that a bone fixation device of the type described herein is configured to be used in the temporal bone of the skull, and the ulna, tibia and fibula styloid processes, or any suitable alternative long bone as desired.

Theintramedullary fixation device1 includes abody50 that defines thehead17 and ashaft52 that extends proximally from thehead17 so as to define an insertion axis that can be defined by thecentral axis14 of theintramedullary fixation device1. Thebody50 can be curved within a plane defined by a longitudinal direction L and a transverse direction T that is oriented substantially perpendicular to the longitudinal direction L. Thehead17 can define a free end that defines a first or distaloutermost end50aof thebody50, and theshaft52 can define a free end that defines a second or proximaloutermost end50bof thebody50 opposite the firstoutermost end50aand spaced from the firstoutermost end50aalong thecentral axis14. The first and second ends50aand50bcan be spaced apart a greater distance along the longitudinal direction L than along the transverse direction T. Thus, thecentral axis14 can extend along both the longitudinal direction L and the transverse direction T. Accordingly, thebody50 can define anupper surface53a, at least a portion of which can be concave in a plane substantially defined by the longitudinal L and transverse T directions, and alower surface53bopposite theupper surface53aalong the transverse direction T, at least a portion of which can be convex in the plane substantially defined by the longitudinal L and transverse T directions. Thebody50 further extends along a lateral direction A that is substantially perpendicular to the longitudinal direction L and the transverse direction T.

Thehead17 can be shaped and dimensioned to reside within the bone structure, such as thestyloid process19 of theradius5, when theintramedullary fixation device1 is disposed within themedullary canal3. In accordance with one embodiment, theshaft52 may be configured to be elastically deformable to conform to the shape of themedullary canal3 during implantation. Thus theshaft52 can be flexible and bowed, which may improve the anchoring of theintramedullary fixation device1 in themedullary canal3. Theshaft52 of theintramedullary fixation device1 can define a longitudinal first fixation element configured to pass across thefracture7 between the first and second bone fragments. Theshaft52 can be substantially smooth and devoid of threads in accordance with one embodiment, such that theintramedullary fixation device1 is an intramedullary nail51 (seeFIGS. 1A-C), or can be threaded as desired such that theintramedullary fixation device1 is an intramedullary screw29 (seeFIGS. 2-3B). Of course, it should be appreciated that any of theintramedullary fixation devices1 described herein can be constructed as a nail or a screw unless otherwise indicated.

Theintramedullary fixation assembly4 can further include at least one, such as a plurality, of second bone fixation elements, such as screws, that are configured to anchor theintramedullary fixation device1 to theradius5, and in particular to thearticular fragment15. For instance, the intramedullary fixation assembly can include a first bone fixation element orscrew9, a second bone fixation element or screw11, and a third bone fixation element orscrew13. Theintramedullary fixation device1 defines ahead17 that is configured to receive respective heads of the first, second, andthird screws9,11 and13, respectively, in thearticular fragment15. Thehead17 can be configured to accommodate thescrews9,11,13, such that a select one of the screws, for instance thethird screw13, may be configured to pass from thearticular fragment15 to theshaft25 so as to fix theshaft25 to thearticular fragment15.

It should be appreciated that the second bone fixation elements can be configured as screws (FIGS. 1A-2) that have a longitudinal core, or staples (FIGS. 3A-B), or the like. The longitudinal cores of the second fixation elements, and also the first fixation element, may be substantially identical in accordance with one embodiment. Having fixation elements with the same core diameter provides the advantage that a reduced number of instruments are able to implant the intramedullary fixation assembly4 (as compared to an assembly comprising elements with differing diameters), thereby reducing the complexity and costs of the implantation procedure. As used herein, the “core” of a screw can refer to the longitudinal shaft of the screw upon which the thread resides.

Theintramedullary fixation device1 can define at least one channel that is configured to receive a corresponding at least one of the fixation elements that can be configured asscrews9,11, and13. In accordance with the illustrated embodiment, theintramedullary fixation device1, for instance thehead17, can include at least one, such as a plurality, of insertion channels that extends through thebody50, each configured to receive a respective one of the bone fixation elements. For instance, theintramedullary fixation device1 can define afirst insertion channel56 that extends through thebody50 and is configured to receive thefirst screw9, asecond insertion channel58 that is configured to receive thesecond screw11, and athird insertion channel60 that is configured to receive thethird screw13. Each of theinsertion channels56,58, and60, respectively, can define aninsertion point56a,58a, and60a, respectively, anexit point56b,58b, and60b, respectively, and achannel axis56c,58c, and60c, respectively, that passes through the respective insertion point and the exit point. The screws9-13 are configured to be inserted into the respective channels56-60 through therespective insertion point56a-60a, along thechannel axis56c-60c, and exit through therespective exit point56b-60b. Thehead17 can define aninsertion area27 in which the insertion points56a-60a, respectively, are located.

As will be described in more detail below with reference toFIGS. 5A-J, theinsertion area27 may be dimensioned and positioned to remain accessible through a single hole in a bone through which the intramedullary nail has been inserted. For instance, the single hole can extend through the styloid process of theradius5. Thus, the insertion points56a-60aof all of the insertion channels56-60 may be located in theinsertion area27. Further,intramedullary fixation device1 may be completely inserted and fixed in position through a single hole in a bone that can extend, for instance, through the styloid process. Fixation of theintramedullary fixation device1 is possible with only a single skin incision and through the making of a single bone hole. Additional locking of the secondoutermost end50bof theintramedullary fixation device1 opposed to theinsertion area27 is unnecessary.

The first andsecond insertion channels56 and58 are configured to receive the first andsecond screws9 and11, respectively, and thethird channel60 is configured to receive thethird screw13. In accordance with the illustrated embodiment, thethird insertion point60aextends through thefirst end50aof thebody50 substantially coextensive with thecentral axis14. Thus, the first and second insertion points56aand58aare spaced from thesecond end50ba distance that is less than the distance that theinsertion point60ais spaced from thesecond end50b.

One of the channels, such as thethird channel60, may be a coextensive channel, such that thethird channel axis60cmay be a coaxial channel axis. At least a portion of thecoaxial channel axis60cmay be substantially coaxial with the insertion axis, and thus thecentral axis14. Theinsertion channel60ccan extend through thebody50 of theintramedullary fixation device1 from itsinsertion point60ato itsexit point60b, the exit point being60blocated in theshaft52. Thecentral axis14 may curve away from thecoaxial channel axis60cin the vicinity of theexit point60bin a direction from theexit point60bto the50bend of theshaft52. Thus, it can be said that at least a portion of the correspondingthird channel axis60ccan be at least partially coaxial, and thus extend longitudinally through (for instance coaxial with, tangential to or intersecting two points of) thecentral axis14 of theintramedullary fixation device1. Thethird exit point60bis disposed on an opposite side of thefracture line7 with respect to thethird insertion point60a. Thus, when thethird screw13 is inserted into thechannel60, a portion of thethird screw13 can cross thefracture line7. Accordingly, two of the screws9-13, such as the first andsecond screws9 and11, respectively, are configured to be entirely located in thearticular fragment15, and at least a portion, for instance a tail, of thethird screw13 is configured to extend longitudinally through theintramedullary fixation device1, and pass from thearticular fragment15 to theshaft25 across thefracture7.

At least one, and up to all of, the channels56-60 can define holes in thehead17 of theintramedullary fixation device1 that are threaded so as to receive threaded heads of the respective screws9-13, thereby increasing the stability of theintramedullary fixation device1. Thus, it can be said that at least one of the plurality of insertion channels, such as thethird insertion channel60, may define a seating area configured to lockingly hold a portion of therespective screws13 therein. The seating area may be located adjacent therespective insertion point60aof the at least one of the plurality ofinsertion channels60, said at least one of theinsertion channels60 has itsexit point60blocated in theshaft52. Each one of the plurality of insertion channels56-60 may have a seating area configured to locking hold a portion of the respective fixation element therein9-13, each seating area located adjacentrespective insertion points56a-60a. Further, the channels56-60 can be configured according to the type of fixation element they are to receive. The fixation elements may be, but are not limited to, one of a locking screw, such as a fixed angle locking screw or a variable angle locking screw, or a staple.

Thecentral axis14 of theintramedullary fixation device1 and at least two, and up to all, of the plurality of channel axes56c-60cmay diverge with respect to each other away from theinsertion area27. For instance, thecentral axis14 and at least one up to all of the plurality of channel axes56c-60c, and thus the respective screws9-13 that are inserted through the channels56-60, pyramidally may diverge with respect to each from theinsertion area27. In accordance with the illustrated embodiment, the first andsecond channels56 and58 diverge from each other with respect to thecentral axis14 along their respective channel axes56cand58c, in a direction from the respective insertion points56aand58ato the respective exit points56band58b. Further, thethird channel60 diverges from least one such as both of the first andsecond channels56 and58 with respect to a lateral axis, along their respective channel axes56c-60c, in a direction from the respective insertion points to the respective exit points. In one embodiment, as shown, for example inFIGS. 1A-C, at least one of channel axes56cand58c, and preferably both, diverge from a vertical plane defined by the transverse direction T and thecentral axis14 at thehead17 by an angle of at least 5°, preferably at least 10°, and more preferably at least 15°, and it is preferred that the twochannels56cand58cdiverge in opposite directions, one medially and one laterally. This angle is advantageously less than 45°, preferably less than 35°, and more preferably less than 30° for eachchannel56cand58c; the angle is thus advantageously between 5° and 35°, more preferably between 5° and 30°. Thechannel axis60ccan diverge from a vertical plane defined by the lateral direction A and the channel axis of one of theinsertion channels56cor58cby an angle of at least 20°, preferably at least 25°, and more preferably at least 35, and is advantageously less than 55°, preferably less than 50°; the angle is thus advantageously between 20° and 55°, more preferably between 25° and 50°.

The screws9-13 are thus mounted to thehead17 of theintramedullary fixation device1 so as to form a pyramidal engagement with theradius5. The pyramidal engagement of the intramedullary fixation device and screws9-13 with theradius5 prevents rotation and separation of thearticular fragment15 and theshaft25, with the exception of micromovements. For instance, theintramedullary fixation assembly4, including theintramedullary fixation device1 and the screws9-11, may restrict motion in up to six dimensions and have the effect of ensuring that thebone fracture7 is stably reduced and thereby supporting healing of theradius5. Thus, the combination of theintramedullary fixation device1 and the three insertion channels56-60 and corresponding screws9-13 is configured to restrict motion of thearticular fragment15 relative to theshaft25 in six dimensions. It should therefore be appreciated that a stable fixation of theradius5 is achieved with the requirement of only one skin incision and one bone hole to implant theintramedullary fixation device1. As a result, a stable fixation of theradius5 can be achieved, while minimal instrumentation can insert theintramedullary fixation device1 and minimal trauma is caused to the patient as few incisions in the skin and bone holes are created.

As described above, thescrews9,11 and13 can havecores9a,11aand13aof equal diameter thereby requiring only one instrument to insert each distal screw. Thescrews9,11 and13 form a pyramidal engagement withbone5, thereby providing a stable fixation of the two bone fragments separated byfracture line7. Thethird screw13 passes acrossfracture line7 in order to increase the stability of the engagement. As can be seen clearly inFIG. 1C, thehead17 of theintramedullary fixation device1 can be configured to receive the first, second, andthird screws9,11 and13 in a manner so as to produce the desired pyramidal engagement. Theintramedullary fixation device1 and screws9,11 and13 can be inserted through thestyloid process19 of theradius5. Advantageously, an entirety of theintramedullary fixation device1 can be inserted through a single bone hole, advantageously using an insertion device30 (seeFIG. 5) for inserting an intramedullary fixation assembly according to the one embodiment.

In accordance with the embodiments illustrated inFIGS. 1A-C, the plurality of insertion channels56-60 may include, and can be limited to, three insertion channels. When implanted, two of thecentral axis14 or the channel axes of the three insertion channels may extend in a direction from thearticular fragment15 to theshaft25 that are separated by thefracture7, and the other two of thecentral axis14 and the channel axes of the three insertion channels may extend within thearticular fragment15.

As illustrated inFIGS. 1A-C, a substantial entirety of the first andsecond insertion channels56 and58 are spaced from each other along the lateral direction A. For instance, the first and second insertion points56aand58acan be at least partially aligned with each other along the lateral direction A. Similarly, the first and second exit points56band58bcan be at least partially aligned with each other along the lateral direction A. Thus, at least a portion of the first and second channel axes56cand58ccan be at least partially aligned with each other along the lateral direction A. The first andsecond insertion channels56 and58 can diverge away from each other with respect to thecentral axis14 along their respective channel axes56band58balong respective directions from the insertion points56aand58ato their respective exit points56cand58c.

At least a portion, for instance thethird insertion point60a, up to an entirety of thethird insertion channel60 can be disposed between the first andsecond insertion channels56 and58 with respect to the lateral direction A. Thethird insertion point60acan further be displaced from the first and second insertion points56aand58aproximally along the longitudinal direction L. For instance, theinsertion point60acan be spaced from thesecond end50ba distance that is less than the distance that the insertion points56aand58aare spaced from thesecond end50b. Further, theinsertion point60a, along with the insertion points56aand58a, extends through the concaveupper surface53aof thebody50, for instance at thehead17. The first andsecond screws9 and11 are thus configured to extend through the respective first andsecond channels56 and58 and anchor to thearticulation fragment15, and thethird screw13 is configured to extend through thethird channel60 and anchor to theshaft52. It should thus be appreciated that theintramedullary fixation device1 defines a region between thethird insertion point60aand thethird exit point60bthat is configured to extend across thefracture7. Thethird insertion point60acan lie on thefirst end50a, which can extend in a plane that is substantially defined by the transverse T and lateral A directions. As illustrated inFIG. 1B, thefirst end50acan extend in a plane that is substantially defined by the longitudinal L and lateral A directions.

In accordance with the embodiment illustrated inFIG. 1C, at least a portion up to all of the first andsecond insertion channels56 and58, including the respective first and second insertion points56aand58a, the first and second exit points56band58b, and the first and second channel axes56cand59c, can be further spaced from each other along the longitudinal direction L as desired. Furthermore, at least a portion up to all of the first andsecond insertion channels56 and58, including the respective first and second insertion points56aand58a, the first and second exit points56band58b, and the first and second channel axes56cand59c, can be aligned with each other along the longitudinal direction L as desired. In accordance with the illustrated embodiment, thethird channel60 can be disposed distal to the first andsecond channels56 and58. For instance, thethird insertion point60a, thethird channel axis60b, and thethird exit point60ccan be disposed distal to the respective first and second insertion points56aand58a, the first and second channel axes56baand58b, and the first and second exit points56cand58c, respectively. Further, in accordance with the illustrated embodiment, thefirst channel56 can be disposed between the second andthird channels58 and60 with respect to the longitudinal direction L. For instance, thefirst insertion point56a, thefirst channel axis56b, and thefirst exit point56ccan be disposed between the respective second and third insertion points58aand60a, the second and third channel axes58baand60b, and the second and third exit points58cand60c, respectively. As described above, the channels56-60, and thus the respective retained screws9-13, can diverge from each other so as to define a pyramidal construct.

Referring now toFIG. 2, theintramedullary fixation device1 can be configured substantially as described above with respect toFIGS. 1A-C, but wherein theshaft52 defines externally threads31 such that theintramedullary fixation device1 defines anintramedullary screw29. Accordingly, theshaft52 can be configured as a bone fixation element that is configured to attach to bone so as to attach theintramedullary fixation device1 to theradius5. Theshaft52 can extend substantially linearly from thehead17, such that thecentral axis14 is likewise substantially linear. Theintramedullary fixation device1 can define first andsecond insertion channels56 and58, and may be limited to two insertion channels. Alternatively, theintramedullary fixation device1 illustrated inFIG. 2 can include any number of channels as described in any one ofFIGS. 1A-1C. In accordance with the illustrated embodiment, at least a portion up to all of the first andsecond insertion channels56 and58, including the respective first and second insertion points56aand58a, the first and second exit points56band58b, and the first and second channel axes56cand59c, can be aligned with each other along the longitudinal direction L as desired.

The first andsecond channels56 and58 extend through theinsertion area27 of thehead17, and can diverge from each other with respect to thecentral axis14 as described above, and theshaft52 can diverge from each of the first andsecond channels56 and58 with respect to a lateral axis, as described above. For instance, the insertion paths may be defined by theshaft52 and the plurality ofinsertion channels56 and58 pyramidally diverging with respect to each other from theinsertion area27. Thus, theshaft52 and the first andsecond screws9 and11 that are inserted in the first andsecond channels56 and58 are configured to define the pyramidal construct described above. The fixation elements, including theshaft52, and the first andsecond screws9 and11, may form a pyramidal engagement with the bone, the angle between the elements at the vertex of the pyramid at the insertion area on the head of the intramedullary nail may all be different or equal and may be 109.5°, or 100°, or 90°, or 80°, or 70°, or 60°. There may be a pair of fixation elements, such asscrews9 and11, in which the angle between them at the vertex of the pyramid is, for example 60° and the third fixation element, for instance theshaft52, is at an angle of 100° from each of the pair of fixation elements.

When implanted in theradius5, one of thecentral axis14 or one of the channel axes56cand58cof the twoinsertion channels56 and58, respectively, may extend in a direction from thearticular fragment15 to theshaft25 that are separated by thefracture7, and the other two of thecentral axis14 and the channel axes56cand58cof the twoinsertion channels56 and58 may extend within thearticular fragment15. For instance, thehead17 can be configured to be disposed in thearticular fragment15, and the threadedshaft52 is configured to extend from thehead17, across thefracture7, and into themedullary canal3 defined by theshaft25 of theradius5. The threads31 can be disposed in at least one or both of thearticular fragment15 and in theshaft25.

It should thus be appreciated thatintramedullary fixation assembly4 can include a bridging element that is configured to attach theshaft25 to thearticular fragment15 through insertion of the bridging element in the vicinity of the single bone hole. When theintramedullary fixation device1 is implanted in theradius5, at least one of theintramedullary fixation device1, such as theshaft52, thefirst screw9 and thesecond screw11 is a bridging element arranged to span across abone fracture7 from thearticular fragment15 to theshaft25, and at least one of theintramedullary fixation device1, such as theshaft52, thefirst screw9 and thesecond screw11 is arranged to lie within thearticular fragment15. The bridging element may have a multi-faceted outer surface for engaging with themedullary canal3 of thearticular fragment15 and theshaft25. When implanted two of the shaft and the first, second and third fixation elements may be bridging elements and the other two of the shaft and the first, second and third fixation elements may lie within the first bone fragment. A fixation element separate from theintramedullary fixation assembly4 may be additionally inserted from thearticular fragment15 to theshaft25 so as to lock thearticular fragment15 and theshaft25 together and restrict motion in six dimensions.

Referring now toFIG. 3A, as described above, the second fixation elements of theintramedullary fixation assembly4 can be configured as staples, such as afirst staple21 and asecond staple22. For instance, each of the first andsecond staples21 and22 can wrap around at least a portion of thebody50 of theintramedullary fixation device1. In accordance with the illustrated embodiment, each of the first andsecond staples21 and22 can wrap around thehead17 of theintramedullary fixation device1 so as to define at least a partial revolution about thehead17. For example, each of the first andsecond staples21 and22 can wrap around theupper surface53aof thehead17, such that opposed free ends of thestaples21 and22 are configured to anchor in thearticular fragment15, and an intermediate portion that extends between the free ends is wrapped about thehead17. The free ends of each staple can be disposed on laterally opposite sides of theintramedullary fixation device1, such that theintramedullary fixation device1 is disposed between the free ends of each of the staples with respect to the lateral direction A. Thefirst staple21 can be spaced from thesecond staple22 along the longitudinal direction L, and the free ends of thestaples21 and22 can be spaced from thehead17 along at least the transverse direction T, for instance in addition to the lateral direction A as desired. Further, the free ends of thefirst staple21 can be offset with respect to the free ends of thesecond staple22 along the lateral direction A, or can be aligned with the free ends of thesecond staple22 along the lateral direction A as desired. Thestaples21 and22 are configured to form an angular construct which provides a stable fixation of the bone fragments separated byfracture line7.

It should be appreciated that theintramedullary fixation assembly4 can include any number of staples as desired. For instance, as illustrated inFIG. 3B, theintramedullary fixation assembly4 can include asingle staple21 that can wrap around at least a portion of thebody50 of theintramedullary fixation device1. In accordance with the illustrated embodiment, the staple21 can wrap around thehead17 of theintramedullary fixation device1 so as to define at a full revolution about thehead17. For example, the staple21 can wrap around theupper surface53aof thehead17 and thelower surface53bof thehead17, such that the opposed free ends the staple21 are configured to anchor in thearticular fragment15, and an intermediate portion of the staple21 that extends between the free ends is wrapped about the head. The free ends of the staple21 can be disposed on laterally opposite sides of theintramedullary fixation device1, such that theintramedullary fixation device1 is disposed between the free ends the staple with respect to the lateral direction A. One of the free end so the staple21 can be spaced from the other of the free ends of the staple21 along the longitudinal direction L, and the free ends of the21 can be spaced from thehead17 along at least the transverse direction T, for instance in addition to the lateral direction A as desired. The free ends of the staple21 are configured to form an angular construct which provides a stable fixation of the bone fragments separated byfracture line7. Thus, it should be appreciated that theintramedullary fixation assembly4 can include at least one staple, such as a plurality of staples that can be wrapped about theintramedullary fixation device1 along at least a partial revolution. Theshaft52 of theintramedullary fixation device1 illustrated inFIGS. 3A-B can be constructed as described above, and can thus be curved and substantially smooth, or can alternatively be externally threaded, as described above. Furthermore, thehead17 can define thechannel60 that is configured to receive a screw that is configured to extend coaxially from thehead17 across thefracture7 to theshaft25 as described above.

Referring now toFIG. 4A, anintramedullary fixation assembly4 can include anintramedullary fixation device24, which can be in the form of a threaded screw having ahead17 and ashaft52 that extends distally from thehead17, that is configured to pass from thearticular fragment15 to theshaft25 across thefracture7. Theintramedullary fixation assembly4 can further include afirst fixation element26, which can be a screw that defines ahead28aand a threadedshaft28bthat extends distally from thehead28aalong a central axis. Theintramedullary fixation device24, and in particular theshaft52, is adapted to extend through anaperture28cthat extends through thehead28aof thefirst fixation element26 at an angle oblique to the central axis of the threadedshaft28bso as to be anchored in theshaft25 of theradius5. Thehead17 of theintramedullary fixation device24 can define externally threads, and theaperture28ccan define internal threads that mate with the external threads of thehead17 so as to attach thehead17 of theintramedullary fixation device24 to thehead28aof thefirst fixation element26. Thefirst fixation element26, and in particular the threadedshaft28b, is configured to anchor thefirst fixation element26, and thus theintramedullary device24, for instance thehead17 of theintramedullary device24, in thearticular fragment15 of theradius5.

Theintramedullary fixation assembly4 can include at least one second fixation element, such as second fixation elements configured asscrews9 and11 that are also received in thehead28aoffirst fixation element26. For instance, thefirst fixation element26 can include at least oneauxiliary aperture28dthat are circumferentially spaced about thehead28a. For instance, theapertures28cand28dcan be equidistantly spaced from each other or spaced from each other at variable distances. Theauxiliary apertures28dcan be configured to receive respective second fixation elements, which can be configured as first andsecond screws9 and11, respectively. In accordance with the illustrated embodiment, the heads of thescrews9 and11 can be externally threaded, and theauxiliary apertures28dcan be internally threaded so as to mate with the heads of the first andsecond screws9 and11 to thereby attach the first and second screws to thehead28a. Thescrews9 and11 are configured to anchor to thearticular fragment15. The shafts of thescrews9 and11 are elongate along respective central axes that are angularly offset with respect to each other, the shaft26b, and theshaft52. Thus, thescrews9 and11, theshaft28b, and theshaft52 can define a pyramidal anchor in theradius5. It should be appreciated that at least some up to all of thescrews9 and11, theshaft28b, and theshaft52 can have the same core diameter.

As illustrated inFIG. 4A, thehead28ais configured to receive a pair ofscrews9 and11. As illustrated inFIG. 4B, theintramedullary fixation assembly4 can include asingle screw9 that is configured to be attached to thehead28a. For instance, thefirst fixation element26 can define a singleauxiliary aperture28dthat extends through thehead28aand is configured to receive and attach to the head of thescrew9 in the manner described above. Thescrew9 is configured to anchor to thearticular fragment15. The shaft of thescrew9 can be angularly offset with respect to thecentral axis14 of theintramedullary device24, such that the shaft of thescrew9, theshaft28b, and theshaft52 can define a pyramidal construct of the type described above.

Referring toFIG. 5A, anintramedullary fixation system33 can include the intramedullary fixation system of the type described above along withinsertion instrumentation62 is configured to insert and fix anintramedullary fixation assembly4 to theradius5. Theinstrumentation62 can include adrilling guide64 that can be made from a radiolucent material, for instance polyetheretherketone (PEEK), and a drill68. The drilling guide64 can include one or more radio-opaque markings66 visible on an x-ray. As used herein, radiolucent can refer to a material that allows the passage of x-rays with little attenuation, thereby rendering the material substantially invisible by x-ray imaging. For instance, the one ormore markings66 can include first and second markings that are aligned with respective first and second trajectories along which the respective second andthird fixation elements11 and13 are to be inserted into thestyloid process19. When the at least one marking66 is aligned as desired, a drill68 can be inserted through thedrill guide64 and guided along a desired trajectory so as to create an opening70 through thestyloid process19, and achannel72 that extends from the opening70 across thefracture7, the channel configured to guide theintramedullary fixation device1 into themedullary canal3. The trajectory defined by the at least one marking66 can be aligned with the opening70, such that the first andsecond screws9 and11 can be inserted into the respective first andsecond channels56 and58 through the opening70.

For instance, referring now toFIG. 5B, theinsertion instrumentation62 can further include aninsertion device30 having an aimingarm34 and apart32, such as a pusher, that is configured to be coupled to the aimingarm34 and urge theintramedullary fixation device1 through the drilled opening70 and into thechannel72, such that theintramedullary fixation device1 can be inserted into the medullary canal. Theintramedullary fixation device1 can be constructed as desired, for instance as described and illustrated above. Thus, the aimingarm34 may be connectable to theintramedullary fixation device1, and may define a plurality ofguide channels34atherein. Eachguide channel34amay have a guide axis aligned with a respective channel axis of an insertion channel of theintramedullary fixation device1, the channel axes diverging from an insertion area defined in ahead17 of theintramedullary fixation device1, as described above.

The aimingarm34 can include, consist of or consist essentially of a radiolucent material. The radiolucent material is polyether ether ketone (PEEK). The aimingarm34 may have an x-ray visible mark. For instance, the aimingarm34 can include one or more radio-opaque markers65 that define the same trajectory or trajectories as previously defined by the one or more radio-opaque markers66 of thedrill guide64 as described above with respect toFIG. 5A. As illustrated inFIG. 5C, a pair of k-wires36 can be inserted through aimingarm34 along the first and second the trajectories as indicated by the radio-opaque markers65, and thus through the drilled opening70 and into thestyloid process19. The K-wires are thus inserted through thehead17 ofintramedullary fixation device1, and in particular through the first andsecond openings56 and58 of the type described above.

Referring toFIG. 5D, theintramedullary fixation system33, for instance theinsertion device30, can further include a measuringdevice38 configured to measure the depth of insertion of a fixation element, such as a screw. The measuringdevice38 that can be added to the top of the aimingarm34 and onto the K-wire36, in order to establish the depth of articular fragment15 (shown to be 28 mm in accordance with the illustration) so that appropriate length screws such as the first andsecond screws9 and11 described above can be selected. Because the first andsecond screws9 and11 are configured to attach to thearticular fragment15, the first andsecond screws9 and11 can be referred to as distal screws. Next, as illustrated inFIG. 5E, the distal screws such as first andsecond screws9 and11 can be inserted over the respective K-wires36 and through the aimingarm34, for instance after the measuringdevice38 has been removed. Next, as illustrated inFIG. 5F, the aimingarm34 can be removed.

After the addition ofdistal screws9 and11, a screw such as thethird screw13 can be inserted through the opening70 and through at least a portion of thehead17 of theintramedullary fixation device1, as described above. For instance, referring now toFIG. 5G, theinsertion instrumentation62 can further include a K-wire sleeve74 that also defines a measuringdevice76, through which a K-wire36 can be inserted along a trajectory that defines an insertion path for thethird screw13. The measuringdevice76 can be placed onto the K-wire sleeve74 so as to measure the insertion depth of the K-wire36, such that an appropriatelysized screw13 can be selected as described above with respect to the measuringdevice38 illustrated inFIG. 5D. Next, as illustrated inFIGS. 5H-5I, thethird screw13 can be inserted through the opening70 and into thethird channel60 so as to extend across the fracture line as described above. Advantageously, implantation of theintramedullary fixation assembly4 using theinsertion instrumentation62 requires only one bone hole, and a single skin incision and minimal instruments, thereby reducing complexity of the procedure, cost and trauma to the patient.

An aspect of the method of the present disclosure embodies the method of using theinsertion instrumentation62 for inserting anintramedullary fixation assembly4 according to any of the embodiments described herein. For instance, a method of implanting an intramedullary fixation device in a medullary canal of a bone can support bone healing of a bone fracture between a first bone fragment and a second bone fragment. The method may have the steps of aligning the first and second bone fragments; making a hole in the cortical bone of the first bone fragment; passing an intramedullary fixation device through the hole, the intramedullary fixation device having a head from which a shaft extends and a plurality of fixation element receiving channels, each one of the plurality of fixation element receiving channels having an insertion point located in an insertion area defined in the head; inserting a first fixation element through an insertion point in the insertion area; and inserting a second fixation element through a different insertion point in the insertion area. A measurement may be taken before insertion of each of the first and the second fixation elements for determining the length of the fixation element to be inserted.

FIGS. 6A and 6B illustrate certain steps of a method of fixing a bone fracture, not using theinsertion device30, for inserting an intramedullary fixation device of the present disclosure. The method may be used to insert an intramedullary fixation assembly of the type disclosed herein, such as that shown inFIGS. 4A and 4B. A 1.1 mm diameter K-wire40 is inserted into the volar-ulnar canal42 of thearticular fragment15 of theradius5. A measuring device of the type described above can then placed on K-wire40 to measure the depth of the articular fragment in order to determine the length required forfirst fixation element26. The measuring device is then removed and a hole is drilled through thestyloid process19, over the K-wire40, using a drill of any size as desired, for instance with a 2.0 mm diameter. Thefirst fixation element26 is then inserted in the hole. After insertion of first fixation element26 a second K-wire40 is inserted in thearticular fragment15 and then a hole is drilled over said K-wire. Using a measuring device on the second K-wire, the desired length of a second fixation element, such as thesecond screw11, is obtained. The measuring device is then removed and thesecond screw11 is inserted into the drilled hole.FIG. 6B illustrates this step in the procedure, viewed down the length ofradius5 from the end ofarticular fragment15. Following insertion of thesecond screw11, a hole for theintramedullary fixation device24 is drilled throughstyloid process19. Because thesecond screw11 is configured to be anchored to thearticular fragment15, thesecond screw11 can be referred to as a distal screw. A length is measured to establish the desired length of theintramedullary fixation device24 using ameasuring device44, which can be configured as described above with respect toFIGS. 5A-I. The measuringpart44 is then removed and theintramedullary fixation device1 is inserted into the hole.

It will be appreciated that this description is by way of example only; alterations and modifications may be made to the described embodiments without departing from the scope of the invention as defined in the claims.

Claims (18)

What is claimed is:

1. A styloid intramedullary fixation device dimensioned to lie within a medullary canal of a distal radius when implanted, the styloid intramedullary fixation device comprising:

a) a curvilinear body having a head portion and an end opposite the head portion, the curvilinear body elongate along a central axis from the head portion to the end such that the central axis lies in a first plane;

b) a first insertion channel configured to accept a first bone screw, the first insertion channel having a first channel insertion point located at the head portion, a first channel exit point from the curvilinear body, and a first channel axis that extends centrally through the first channel insertion point and the first channel exit point such that, as the central axis extends in a direction from the head portion to the end, the central axis converges with the first channel axis at a select side of the first channel axis, then is tangent to the first channel axis at a tangent location, and then diverges from the first channel axis at the select side; and

c) a second insertion channel configured to accept a second bone screw, the second insertion channel having a second channel insertion point located at the head portion, a second channel exit point located at the head portion, and a second channel axis that extends centrally,

wherein the tangent location is disposed between the end and the second channel axis on a second plane that extends through the end, the tangent location, and the second channel axis, and the styloid intramedullary fixation device is devoid of an insertion channel that is configured to accept a bone screw and that has an exit point that is positioned closer to the end than the first channel exit point is positioned to the end.

2. The styloid intramedullary fixation device ofclaim 1, wherein the central axis, the first channel axis, and the second channel axis each diverge with respect to each other.

3. The styloid intramedullary fixation device ofclaim 2, wherein the head portion comprises an insertion area and wherein the first and second channel insertion points are located within the insertion area.

4. The styloid intramedullary fixation device ofclaim 1, further comprising a third insertion channel configured to accept a third bone screw, the third insertion channel having a third channel insertion point located at the head portion, a third channel exit point located at the head portion, and a third channel axis that extends centrally through the third channel insertion point and the third channel exit point.

5. The styloid intramedullary fixation device ofclaim 4, wherein the third channel axis diverges from the first plane in the direction from the head portion to the end.

6. The styloid intramedullary fixation device ofclaim 4, wherein the central axis, the first channel axis, the second channel axis, and the third channel axis each diverge with respect to each other.

7. The styloid intramedullary fixation device ofclaim 4, wherein the curvilinear body includes an upper surface and a lower surface opposite the upper surface, each of the upper surface and the lower surface extends from the head portion to the end, and a third plane that includes the first channel axis intersects both the second channel axis and the third channel axis at respective locations between the upper surface and the lower surface.

8. The styloid intramedullary fixation device ofclaim 1, wherein the first channel axis is substantially coextensive with the central axis.

9. The styloid intramedullary fixation device ofclaim 1, wherein the curvilinear body includes an upper surface and a lower surface opposite the upper surface, each of the upper surface and the lower surface extends from the head portion to the end, and the tangent location is between the upper surface and the lower surface.

10. A styloid intramedullary nail dimensioned to lie within a medullary canal of a distal radius when implanted, the styloid intramedullary fixation nail comprising:

(a) a rigid curvilinear body elongate along a central axis of the styloid intramedullary fixation nail, the curvilinear body having a head portion and a shaft portion terminating in an end opposite the head portion, the head portion defining a first width that is measured along a straight line perpendicular to the central axis, and the shaft portion defining a second width that is measured along a straight line perpendicular to the central axis and that is less than the first width, the central axis extending along a length of the body from the head portion to the end such that the central axis lies in a first plane, the head portion of the body defining a proximal surface transverse to the central axis at a proximal end of the body;

(b) a first insertion channel having a first channel insertion point extending into the curvilinear body via the proximal surface of the head portion of the body and a first channel exit point from the curvilinear body, the first insertion channel configured to accept a first bone screw, the first insertion channel defining a first channel axis that extends centrally through the first channel insertion point and the first channel exit point such that the first channel axis intersects the central axis at a first point and a second point spaced from the first point along the length of the body; and

(c) a second insertion channel having a second channel insertion point into the curvilinear body and a second channel exit point from the curvilinear body, the second insertion channel configured to accept a second bone screw, the second insertion channel defining a second channel axis that extends centrally through the second channel insertion point and the second channel exit point, the second channel insertion point and exit point located within the head portion;

wherein the second channel axis diverges from the first plane, and the first channel axis diverges from a second plane that is orthogonal to the first plane.

11. The styloid nail ofclaim 10, wherein the first channel axis is substantially coextensive with the central axis.

12. The styloid nail ofclaim 10, wherein the second channel axis diverges from the first plane at a second channel axis angle of at least 5°, and the first channel axis diverges from the second plane at a first channel axis angle of at least 20°.

13. The styloid nail ofclaim 12, wherein the second channel axis angle is at least 10°.

14. The styloid nail ofclaim 13, wherein the first channel axis angle is at least 30°.

15. The styloid nail ofclaim 14, further comprising a third insertion channel having a third channel insertion point into the curvilinear body and a third channel exit point from the curvilinear body, the third insertion channel configured to accept a third bone screw, the third insertion channel defining a third channel axis that extends centrally through the third channel insertion point and the third channel exit point, the third channel insertion point and exit point located within the head portion.

16. The styloid nail ofclaim 15, wherein the third channel axis diverges from the first plane at an angle of at least 5°.

17. The styloid nail ofclaim 10, wherein the curvilinear body has a rigidity sufficient to stably reduce a bone fracture and restrict motion of the portions of the bone in a plurality of dimensions.

18. The styloid nail ofclaim 10, wherein the curvilinear body has a rigidity sufficient to restrict motion of the portions of the bone in six dimensions.

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